///////////////////////////////////////////////////////////////////////////////////
/// OpenGL Mathematics (glm.g-truc.net)
///
/// Copyright (c) 2005 - 2015 G-Truc Creation (www.g-truc.net)
/// Permission is hereby granted, free of charge, to any person obtaining a copy
/// of this software and associated documentation files (the "Software"), to deal
/// in the Software without restriction, including without limitation the rights
/// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
/// copies of the Software, and to permit persons to whom the Software is
/// furnished to do so, subject to the following conditions:
/// 
/// The above copyright notice and this permission notice shall be included in
/// all copies or substantial portions of the Software.
/// 
/// Restrictions:
///		By making use of the Software for military purposes, you choose to make
///		a Bunny unhappy.
/// 
/// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
/// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
/// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
/// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
/// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
/// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
/// THE SOFTWARE.
///
/// @ref gtx_gradient_paint
/// @file glm/gtx/gradient_paint.inl
/// @date 2009-03-06 / 2013-04-09
/// @author Christophe Riccio
///////////////////////////////////////////////////////////////////////////////////////////////////

namespace glm {
    template<typename T, precision P>
    GLM_FUNC_QUALIFIER T
    radialGradient
    (
            tvec2<T, P>
    const & Center,
    T const &Radius,
            tvec2<T, P>
    const & Focal,
    tvec2 <T, P> const &Position
    ) {
    tvec2 <T, P> F = Focal - Center;
    tvec2 <T, P> D = Position - Focal;
    T Radius2 = pow2(Radius);
    T Fx2 = pow2(F.x);
    T Fy2 = pow2(F.y);

    T Numerator = (D.x * F.x + D.y * F.y) +
                  sqrt(Radius2 * (pow2(D.x) + pow2(D.y)) - pow2(D.x * F.y - D.y * F.x));
    T Denominator = Radius2 - (Fx2 + Fy2);
    return Numerator /
    Denominator;
}

template<typename T, precision P>
GLM_FUNC_QUALIFIER T
linearGradient
(
        tvec2<T, P>
const & Point0,
tvec2 <T, P> const &Point1,
        tvec2<T, P>
const & Position
)
{
tvec2 <T, P> Dist = Point1 - Point0;
return (Dist.
x *(Position
.x - Point0.x) + Dist.
y *(Position
.y - Point0.y)) /
glm::dot(Dist, Dist
);
}
}//namespace glm
